1. Field of the Invention
In general terms, my invention relates to in vitro medical care for the pre-implantation patient. More specifically, my invention relates to a new use for quantum well infrared photodetector (QWIP) technology: monitoring and maintaining the body temperature of human embryos and hatchlings in an engineered environment. The engineered environment is preferably a micro intensive care unit (xcexcICU).
A human is an embryo only from conception to hatching. Hatching is an event that takes place when an embryo escapes the shell of the egg that he or she was conceived in. A human is a hatchling only from hatching until implantation (nidation).
2. Prior Art
The quantum well infrared photodetector (QWIP) camera was invented by Sarath Gunapala at NASA""s Jet Propulsion Laboratory. (U.S. Pat. No. 6,211,529. Gunapala et al. Infrared radiation-detecting device.) QWIP technology has yielded one of the most sensitive yet affordable handheld long-wavelength infrared cameras. A QWIP camera may have a thermal sensitivity as sharp as 20 mK (twenty thousandths of one Kelvin degree). OmniCorder Technologies (Stony Brook, N.Y.) manufactures its BioScanIR System for imaging and recording thermal data from adult, pediatric, and neonatal patients using a QWIP camera.
Infrared cameras are generally better at picking out actual differences in temperature than they are at picking out actual temperatures. A measure of imaging performance, thermal sensitivity validates a numerical difference between two or more temperature measurements on a thermal imaging map. This form of relative measurement is meant to reflect a real temperature difference between points on the map. In contrast, thermal accuracy validates a numerical identity between a temperature measurement and the corresponding real temperature. This form of absolute measurement is meant to establish a number reflecting the real temperature of a point on the map. A point on the map can serve as a reference temperature when it is known with greater thermal accuracy than the thermal accuracy specified for the camera. Depending on the accuracy of the reference, the camera may yield an effective thermal accuracy nearly equal to its thermal sensitivity.
Heat lamps emit infrared radiation to provide a heating source. Heat lamps are often used to warm neonates, especially if they are born premature. An infrared light emitting diode (LED) emits infrared radiation on a very small scale. The shell of a human embryo""s egg covers an inner diameter of approximately 100 microns (0.1 millimeters) at fertilization and has a spherical shape. Because human embryos and hatchlings are so small, an infrared LED can generate enough heat to warm the baby.
Miriam Menkin discovered the first reported human in vitro fertilization in 1944, with support from Harvard physician John Rock. (Marsh M. and Ronner W. The Empty Cradle: Infertility in America from Colonial Times to the Present. Baltimore, Johns Hopkins University Press, 1996. p. 171-209.) Death of the child introduced the problem of xe2x80x9cmiscarriage in vitroxe2x80x9d. Today there is a growing effort to reduce miscarriage in vitro by engineering better environments. Yet this effort has been impeded by some experts who prefer unimaginative reliance on crude petri dish methods.
We are arriving at the point where as humans we will be able to care for our children from conception with the utmost intelligence and resource. Ironically, the last steps are not technology. They are simply courage.
Although micromanipulation techniques and petri dish practices have been employed since the inception of human in vitro fertilization, the advent of a new branch of engineering called micro electro mechanical systems (MEMS) has sparked interest in improving the technology of in vitro fertilization. To this end, David Beebe et al. have invented a MEMS-based means of providing embryos and hatchlings with fluidic ventilation. (U.S. Pat. No. 6,193,647. Beebe et al. Microfluidic embryo and/or oocyte handling device and method.)
By promoting child health and strength up until the time of being introduced to the maternal body, engineered environments will make pregnancy more survivable for children created and first cared for outside the maternal body. This benefit comes in addition to the benefit of reducing in vitro miscarriage itself.
My institution, Juridic Embassy, has sponsored new progress in fertility care, in an effort to advance diplomatic regard for the rights of children as patients in medicine. As a consequence of my research in this area, I initiated the Micro ICU Project in response to the general lack of care being provided to children created by in vitro fertilization. The synergy of the project was created by the needs of the children in light of impressive new engineering technologies, particularly MEMS. Using integrated microfabrication technologies (IMT) such as complementary metal oxide semiconductor technology (CMOS) and MEMS, as well as various large-scale technologies, the goal of the project is to perfect an elaborately engineered environment called a micro intensive care unit, or xcexcICU, for human embryos and hatchlings.
One objective of the Micro ICU Project is to provide a means to monitor and maintain body temperature. This objective provides the subject matter of my present invention.
3. Statement of the Necessity
In modern fertility programs, human embryos and hatchlings are incubated outside the maternal body in a fluid incubation medium. Prior art methods of temperature monitoring and maintenance rely exclusively on a measurement of the temperature of the fluid incubation medium. The temperature of the medium is set to 37 degrees Celsius using a temperature-controlled incubator oven or microscope stage warmer.
However, because of endogenous heat production, which is the heat produced by a baby""s own body, the baby""s body temperature can differ from the ambient temperature of the surrounding environment or medium. Accordingly, the baby can become overheated, leading to exhaustion, dysfunction, and death, when only the temperature of the environment is controlled. (Cone T. E. Jr. History of the Care and Feeding of the Premature Infant. Boston: Little, Brown, 1985. p. 21-22.) Thus, a problem with the prior art in the field of in vitro fertilization is its focus on the temperature of the fluid incubation medium, instead of on body temperature itself.
What is needed to modernize the art of in vitro fertilization is a method to monitor and maintain the baby""s actual body temperature.
To monitor the body temperature of a human embryo or hatching: attach a quantum well infrared photodetector (QWIP) camera to a microscope and use appropriate computer technology to thermally image the embryo or hatchling.
To maintain the body temperature of a human embryo or hatchling: keep the fluid incubation medium slightly below optimum body temperature to ensure cooling can occur if the body becomes overheated; provide an added source of heat by focusing tiny heat lamps on the body of the embryo or hatchling; cycle the heat lamps on and off or apply them with varying intensity to maintain optimum body temperature in accordance with body temperature measurements obtained by the above-stated monitoring method.